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Synthesis of an Interference-Resistant Space-Time Filter for High-Precision Measurements of Navigation Parameters According to the Signals of Global Navigation Satellite Systems

We study the problems of serviceability of contemporary high-precision terminals of global navigation satellite systems under the conditions of jamming and spoofing interferences. The application of digital antenna arrays with algorithms of space-time signal processing of the signals can be regarded as a solution of the problem of low interference resistance. We describe well-known, most studied, and currently applied algorithms of space-time signal processing. We also formulate the causes that do not enable one to use well-known algorithms in high-precision terminals of satellite systems of global navigation. We propose an algorithm of space-time signal processing based on a space-time filter of finite length with a theoretically justified requirement of Hermitian symmetry for the matrix impulse response. The proposed algorithm guarantees the absence of distortions of signals under any signal and interference conditions. In this case, the impulse response of the space-time filter is computed according to the criterion of optimal suppression of the interference. The characteristics of the proposed space-time filter and other algorithms of space-time signal processing are investigated. For this purpose, we apply the method of mathematical simulation with random search of numerous parameters of signals and interferences (directions to signals, directions to numerous interferences, and to their reflections, remoteness of the reflectors of interferences, the phases of reflections, and the levels of interferences and reflections, etc.). The results of simulations are presented in the form of the distribution functions of the signal-to-interference ratios at the output of the algorithms of space-time signal processing and the distribution functions of the phase and signal-time biases. The obtained dependences substantiate the absence of the phase and signal-time biases in the space-time filter for any signal and interference conditions with interference multipath. It is shown that the space-time filter guarantees a higher interference resistance than the compensating algorithms of space-time signal processing.

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APPLICATION OF A CONVOLUTIONAL NEURAL NETWORK AND A KOHONEN NETWORK FOR ACCELERATED DETECTION AND RECOGNITION OF OBJECTS IN IMAGES

One of the most effective ways to improve the accuracy and speed of algorithms for searching and recognizing objects in images is to pre-select areas of interest in which it is likely to detect objects of interest. To determine areas of interest in a pre-processed radar or satellite image of the underlying surface, the Kohonen network was used. The found areas of interest are sent to the convolutional neural network, which provides the final detection and recognition of objects. The combination of the above methods allows to speed up the process of searching and recognizing objects in images, which is becoming more expedient due to the constantly growing volume of data for analysis. The process of preliminary processing of input data is described, the process of searching and recognizing patterns of aircraft against the underlying surface is presented, and the analysis of the results is carried out. The use of the Kohonen neural network makes it possible to reduce the amount of data analyzed by the convolutional network by 18–125 times, which accordingly accelerates the process of detection and recognition of the object of interest. The size of the parts of the input image fed into the convolutional network, into which the zones of interest are divided, is tied to the image scale and is equal to the size of the largest detectable object, which can significantly reduce the training sample. Application of the presented methods and centering of the object on training images allows accelerating the convolutional network training by more than 5 times and increasing the recognition accuracy by at least 10%, as well as minimizing the required minimum number of layers and neurons of the network by at least halving, respectively increasing its speed

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APPLICATION OF A CONVOLUTIONAL NEURAL NETWORK TO CREATE A DETECTOR OF TECHNICAL ANALYSIS FIGURES ON EXCHANGE QUOTES CHARTS

Today, the use of artificial intelligence based on neural networks is the most effective approach to solving image recognition problems. The possibility of using a convolutional neural network to create a pattern detector for technical analysis based on stock chart data has been investigated. The found figures of technical analysis can serve as the basis for making trading decisions in the financial markets. In the conditions of an ever-growing array of various information, the use of visual data reading tools is becoming more and more expedient, as it allows to speed up the process of searching and processing the necessary information for decision-makers. The modeling process, analysis, and results of applying the pattern detector of technical analysis are presented. The general approach to the construction and learning of a convolutional neural network is also described, and the process of preliminary processing of input data is described. Using the created detector allows to automate the search for patterns and improve the accuracy of making trading decisions. After finding the patterns, it becomes possible to obtain additional stock statistics for each type of figure: the context in front of the figures, the percentage of successfully completed figures, volume analysis, etc. These technical solutions can be used as expert and trading systems in the stock market, as well as integrated into existing ones.

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